1. Field of the Invention
The present invention relates to a graphic recording apparatus, primarily used in an industrial laboratory, for recording measurement data graphically by plotting lines representing the measured data on a recording paper in a form of a graph.
2. Description of the Background Art
In an industrial laboratory, the data obtained by the measurement are often recorded graphically by using a graphic recording apparatus of various types such as a multiple colored pen line plotter type, an impact dot plotter type, an ink jet plotter type, and a thermographic plotter type.
In such a graphic recording apparatus, the measurement data given by outputs of measurement devices are taken in as multi-channel inputs and are plotted on a recording paper in a form of a graph in which the measurement data of each channel is represented by a line plotted on the recording paper.
However, each type of such a conventional graphic recording apparatus has been associated with the following drawbacks.
First, in a graphic recording apparatus of a multiple colored pen line plotter type, a configuration of the apparatus becomes increasingly large and complicated as a number of colored pens used in the apparatus increases, such that an apparatus using five or more colored pens has been practically too large and too complicated. Thus, in this type of a conventional graphic recording apparatus, a recording of the measurement data with five or more channels has been difficult.
On the other hand, in a graphic recording apparatus of an impact dot plotter type, the configuration of the apparatus can be simplified compared with the multiple colored pen line plotter type such that the apparatus itself can be made in a compact size, but the measurement data are represented by dotted lines such as dotted lines 101 shown in FIG. 1, so that it has been difficult to deal with the measurement data involving quick and minute changes.
As for a graphic recording apparatus of an ink jet plotter type or a thermographic plotter type, the simplification of the configuration of the apparatus can be achieved, but all the measurement data are represented by monochromatic continuous lines such as continuous lines 102 shown in FIG. 2, so that the recorded data on the recording paper become increasingly congregated to make it harder to distinguish each channel and read off each data accurately as a number of channels of the measurement data increases.